Manufacture of miniature lamps



March 18, 1941. w. E. CARPENTER IANUFACTURE 0F IINIATURE MIPS Filed July 15, 1938 AMW- ATTORNEY KNVENTOR Blf/N6;

Patented Mar. 18, 1941 UNITED sTATEs PATENT OFFICE I: Manufacturing Company, laat Pittsburgh, Pa., a corporation of Pennsylvania Application Illy 15, 1938, Serial No. 219,344

This invention relates to the manufacture of miniature lamps for automobiles, ilashlighta, and other purposes, and more particularly to such by an economical continuous process from glass 5 tubing of the proper size, adapted to make use of a machine.A

The principal object of my invention, generally considered, is the manufacture of miniature lamps by a method which avoids a number of undesired incidents of the conventional method.

Another object of my invention is the manufacture of miniature lamps by a method in which a bulb is blown from glass tubing, the tube portion at one end being restricted for exhaust purposes and held to normal size at the other end for reception of the mount and sealing-in of the lead wires.

A further object of my invention is the manufacture of miniature lamps in which shorted bases, due to lead wires touching the base shell, and leakers due to burned or oxidized leads, are eliminated.

A still further object of my invention is the manufacture of miniature lamps in which provision is made for better axial alignment and light center length control at the sealing-in process.

An additional object of my invention is the provision of a method ot manufacturing miniature lamps which can be used in connection with prefocusing.

Another object of my invention is the development of a method of manufacturing miniature lamps in which the mounting and sealing are done on one machine without disturbing the mount or leads.

A further object of my invention is the provision of a miniature lamp having a bulb providedV with a groove molded therein to receive the top edge of a prefocusing bue, whereby a chuck at sealing may ilt the groove in me same manner as the precision base, and in which the collar may be integral with the base.

45 A still further object of my invention is the manufacture of miniattn'e lamps in which the correct light center length is obtained by having two spools of dumet, or other lead-in conductor wire, on eachhead from which to feed lead wires, the mount being pulled down by means oi the lead feeding blocks, and a lead straightening device being mounted on each head, the leads being cut oi! after the sealing is complete.

Other objects and advantages of the invention.

relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing- Figs. 1 is a side elevational view of a miniature lamp having a prefocusing base, and constructed 5 in accordance with my invention.

Fig. 2 is a view corresponding to Fig. 1, except that the lamp base is shown partly broken away and the direction of view is at right angles to that of Fig. 1.

Fig. 3 is an elevational view showing a piece of tubing being heated preparatory to blowing a bulb therein.

Fig. 4 is a view corresponding to Fig. 3, but showing the appearance of the tubing in the next step of the process where a bulb has been blown in an associated mold, said mold and portions of the tubing and bulb blown therein being shown in vertical section.

Fig. 5 is a view corresponding. to Fig. 4, but showing fires acting on the glass tube above the bulb for the purpose of contracting it in section too provide an exhaust tube portion, the sealed end portion of the tubing, or that below the bulb, being acted on by iires for the purpose of cutting oii said sealed portion.

Fig. 6 is a view corresponding to Fig. 5, but showing the sealed portion of the tube removed and the mount disposed beneath the bulb and supported on the lead feeding block preparatory to insertion in place.

Fig. 7 is a View corresponding to Fig. 6, but showing the mount in place in the bulb, and fires in the process of sealing the neck of the bulb around the mount leads.

Fig. 8 is a. view corresponding to Fig. 7, but showing the mount leads sealed into the lower 'portion of the bulb, and air pressure applied to stretch the seal.

Fig. 9 is a View corresponding to Fig. 8, but showing the bulb under exhaust and the lead wilbeing cut oi to proper length.

Fig. l is a view corresponding to Fig. 9, but showing the exhaust tube being tipped ofi, while the lower portion of the mold which forms the groove is removed, and one of the leads bent up preparatory to application of the base.

Fig. 11 is a view corresponding to Fig. 10, but showing the position of the parts after the base has been actually moved up into registering relation with respect to the bulb.

Miniature or flashlight lamps are now customarily manufactured by, first, forming the mount by applying a glass bead over two pieces of lead wire cut to length, fusing said bead over the wire, and fastening the filament in place on the short ends of the wire adjacent said bead. 'I'he formed mount with the leads spread, is then dropped in the bulb while the latter is positioned upside-down, the spread leads holding it in proper position. 'I'he assembled bulb and mount are then fed to a machine where an exhaust tube is fed into engagement with the open-ended portion of the bulb and nally sealed thereto, leaving the leads protruding from the sides at the junction between the exhaust tube and the bulb. The assembled members are then reversed in position and transferred to the exhausting machine where the bulb is evacuated and the exhaust tube heated to effect the tipping-off operation. 'I'he exhausted and tipped-off lamp is then removed to another machine for basing.

In accordance with my invention, I eliminate several of the defects sometimes found in lamps manufactured in accordance with the aforedescribed method, such as shorted bases due to lead wires touching the base shell, leakers due to burned or oxidized leads, faulty axial alignment and light center control and impossibility of use in connection with prefocusing.

Referring to the drawing in detail, Fig. 3 shows a piece of glass tubing I2, the lower end portion of which is sealed as indicated at I3, as from a previous tipping-off operation, and rotatably received in a bearing or holder I4. Fires I5 and I6 are allowed to play on the tube above the sealed portion I3, while the same is rotated, as indicated by the arrow I1, and puddled after softening to form the desired amount of glass for blowing the bulb.

A mold, formed in two parts I8 and I9, with groove-forming portions 2| and 22, is applied around the softened portion of the tube I2, as shown in Fig. 4, and a bulb 23 blown therein, as by the application of air pressure, indicated by the arrow 24. The bulb 23 is desirably blown while the tube is rotated, as indicated by the arrow 25, thereby avoiding the formation of seams at the joints of the mold portions I8, I9, 2|, and 22. By virtue of the portions 2l and 22, the bulb as blown has an angular or V-shaped groove 26 around the portion thereof between the neck 21 and the generally spherical portion 23, for the reception of the free or upper edge of the base 29.

Fig. 5 shows the blown bulb 23 in the mold I8-I9, and the lower or sealed portion I3 being removed by the hot-cutting fires 30 disposed beneath baiiie means 3|, the portion of the tube I 2 above the bulb 23 being desirably at the same time reduced in section, as by means of the fires 32, to provide an exhaust portion 33 which may be readily tipped E. In the figure under consideration, the bulb 23 is assumed to be stationary and the res 30 and 32 rotating.

In Fig. 6 the bulb 23 is shown with the sealed portion I3 removed and the bead-mount 34 about to be introduced through the neck portion 21 of .the bulb 23. 'I'he bead-mount 34 is supported on the outer lead feeding block 35, and may have been formed by feeding strands 35 and 31 of dumet, or other lead wire, from two spools thereof (not shown) through a bead 38, heating said bead -to consolidate the same with said lead wires, and applying a lament 39 on the free or upper ends of said lead wires, as by crimping in the conventional manner.

The mount 34 may be introduced into the bulb 23 in any desired manner, as by raising the mount 34 to position in the bulb, as by upward movement of both the outer block 35 and a greater upward movement of the inner feeding element 43, or by lowering the mold portions and enclosed bulb 23 over the mount, while the latter is raised by upward movement of the feeding Velement 40, to -the position shown in Fig. '1.

In accordance with Fig. 7, the baille means 3| is again applied, to protect the bulb, while the fires 4I act on the neck portion therebeneath, to consolidate the same about the mount leads 36 and 31.

In Fig. 8, the sealing of the neck portion 21 by the fires 4I is ,shown completed, either by merely softening the glass'by said fires to a sufcient extent so that they fuse around the leads 35 and 31, or by pinching said softened glass about said leads by means of suitable clamping jaws, not shown. If clamping jaws are not employed, air pressure is desrably introduced into the tube I2, as indicated, to stretch the seal about the leads 35 and 31 and avoid a thick mass of glass at this point. Fig. 9 shows the lead feeding block 35 dropped, and cutting jaws 42 and 43 employed to trim the leads 35 and 31 to the desired length, the bulb 23 being desirably exhausted at the same time, as indicated by the arrow 44.

In accordance with Fig. 10, the groove forming portions 2| and 22 are removed, one of the leads, as 38, bent upwardly, as shown, to position for the reception of the base 29 and tipping-off res 45 employed for sealing the tube I2 above the bulb 23.

Fig. 11 shows the base 29 assembled with the bulb 23, and in the process of being sealed thereto, as by means of cement 45, the lead 31 passing through a center aperture 41 for forming one contact, and the lead 36 engaging the edge portion of the base 29, and being soldered thereto, as indicated at 48, to connect it to the shell of. said base.

VIn the present embodiment, the base is shown as one of the precision type having a flange 49 outstanding from the cylindrical portion I and slotted, as indicated at 52 and 53, to connect with suitable positioning buttons (not shown) on the device to which attached. The lamp being now completely formed, the mold portions I8 and I9 may be removed, leaving the finished lamp, as shown in Figs. 1 and 2.

The sealed portion of the tube I2, cut off as shown in Fig. l0, may now be inserted in the holder I4, the fires I5 and I 5 applied to the tube thereabove, and the lamp-forming operation repeated.

From the foregoing disclosure, it will be seen that I have provided an improved method or process of manufacturing miniature lamps, in which the bulbs thereof are blown one after another from portions of a length of tubing, the lower or free end of said tubing forming the neck of the bulb, or the portion with which the mount is consolidated, and the other portion of the tubing being removed after exhausting the bulb, leaving a tip at the top end, or that opposite .the portion with which the mount is consolidated.

As an alternative to keeping the bulb in the mold until it is completely finished, including the basing operation, I may transfer the lamp to the exhaust machine after the leads are cut off, as shown in Fig. 9, and the lamp removed from the mold, after which it may be transferred to the basing machine. As an alternative to blowing bulbs from long pieces of tubing. I may, instead,

apply cut pieces from each of which one bulb may be formed.

In accordance with my invention, I have provided a novel form of bulb which is integral with a portion of the tube from which blown at one end, and another portion at the other end, one portion of said tube eventually forming the tip after exhausting, and the other forming the neck or portion which receives and is consolidated with the mount.

By virtue of my improved method, I have been able to accomplish a number of results which former methods failed to secure. For example, in accordance with former methods, the leads, after the bead mount was consolidated with the bulb, stuck out from the neck portion of the bulb and came so close to the base that shorting was apt to occur. By keeping the leads of lamps, constructed in accordance with my invention, together until after consolidation with the bulb neck and then bending only one, rather than both, outwardly, this condition has been remedied.

By always having the leads protected by surrounding glass during the process of consolidating the mount with the bulb, I have avoided .the development of leakers due to burnt or oxidized leads. By keeping the leads straight in the feeding block, and the bulb in the mold during the period of consolidation between the mount and bulb, I have produced better axial alignment and light center length control, thereby also making it possible to use my process in connection with prefocusing and the use of a prefocusing or precision base, as illustrated. It will also be seen that, as distinguished from prior processes, I am able to effectuate the mounting and sealing on one machine, without disturbing the mount or the leads.

On account of molding a groove in the bulb to receive the top edge of a prefocusing base, the same may be applied as a precision base and have a collar integral therewith as disclosed.

I may secure the correct light center length by having two spools of dumet, or other lead wire, on each head from which to feed such wires, this, arrangement also allowing for pulling down the mount by means of the lead feeding blocks, as an alternative or supplement to stretching the glass around the lead wires by means of air pressure. A lead straightening device is also desirably mounted on each head.

Although a preferred embodiment of my invention has been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

l. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end thereof, to provide a tubular portion of normal size at each end.

2. The method of making a miniature incandescent electric lamp, comprising heating to soften a portion of a glass tube adjacent a sealed end thereof between unsoftened tubular portions, and blowing a bulb from said softened portion, while rotating said tube in a support at its sealed end.

3. The method of making a miniature incandescent electric lamp, comprising heat-softening a portion of a glass tube adjacent a sealed end thereof between unsoftened tubular portions, applying a mold around said softened portion, and blowing a bulb in said mold, while rotating said tube in a support at its sealed end.

4. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a. sealed end thereof, to provide a tubular portion of normal tube size at opposite ends, and cutting off the sealed end of said tube to leave an open neck portion on said bulb, in addition to the tubular portion at the other end thereof of normal tube size.

5. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end thereof. to provide a tubular portion of normal tube size at opposite ends, cutting off the sealed end to leave an open neck portion, in addition to the portion of said tube at the other end of said bulb, and heating said lastmentioned tubular portion to form a contraction therein.

6. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end thereof, to provide a tubular portion of normal tube size at opposite ends, cutting on' the sealed end to leave an open neck portion, in addition to the tubular portion at the other end thereof, heating said last-mentioned tubular portion adjacent said puib to provide a contraction, and introducing a mount into said bulb through said open neck portion.

7. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end, to provide a tubular portion of normal tube size at opposite ends, cutting on.' the sealed end to leave an open neck portion on said bulb, in addition to the tubular portion at the other end thereof, reducing the section of said last-mentioned tubular portion, introducing a mount into said bulb through said open neck portion, and heating said neck portion to consolidate it with said mount.

8. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end thereof, to provide a tubular portion of normal tube size at opposite ends, cutting of! the sealed end of said tube to leave an open neck portion on said bulb, in addidtion to the tubular portion at the other end thereof, introducing a bead mount into said bulb through said open neck portion and positioning it at the proper sealing height, heating the neck portion of said bulb to consolidate it around said mount, and exhausting said bulb through said glass tube.

9. The method of making a miniature incandescent electric lamp, comprising blowing a bulb in an intermediate portion of a glass tube adjacent a sealed end thereof, to provide a tubular portion of normal tube size at opposite ends, cutting off the sealed end to leave an open neck portion, in addition to the tubular portion at the other end thereof, introducing a bead mount through said open neck portion and positioning it at the proper sealing height, heating the neck portion to consolidate it around said mount, exhausting said bulb through said glass tube, and

cutting off the leads of said mount to the proper mold so that the shouldered portion leaves a baseedge-receiving groove, cutting olf the sealed end of said tube to leave an open neck portion, in addition to the tubular portion at the other end thereof, heating said last-mentioned tubular portion to provide a contraction therein, inserting a mount in said bulb and positioning it at the proper sealing height, heating the neck portion of said bulb to melt it around the leads of said mount and sealing the latter in said bulb, pulling down on the leads to stretch the seal and using air pressure for that purpose, exhausting said bulb through said tube in which the blowing pressure was applied, cutting oiI and spacing the leads, and applying a base to said bulb.

11. A tube with a miniature lamp bulb blown therein near one end, leaving a neck portion of normal tube size to receive a mount, the tube portion at the diametrically opposite side of said bulb being contracted for exhaust purposes.

12. In combination, a bulb having an exhaust tip at one end and a bead mount consolidated with a neck portion at the other end independent of the exhaust tip end, said neck portion being provided with an angular groove molded therein, and a base having its edge portion tting said groove and cemented to said bulb.

13. 'Ihe method of making a miniature incandescent electric lamp, comprising feeding a sealed glass tube to heating means to soften and puddle a portion adjacent the sealed end, applying a shouldered mold around said softened portion, blowing a bulb in said mold so that the shoulder portion leaves a base-edge-receiving groove, cuttng oi the sealed end of said tube to leave an open neck portion, in addition to the tubular portion at the other end thereof, heating said last mentioned tubular portion to provide a contraction therein, inserting a mount in said bulb and positioning it at the proper sealing height, heating the neck portion of said bulb to melt it around the leads of said mount, and sealing the latter in said bulb, pulling down on the leads to stretch the seal, exhausting said bulb through the tube from which it was originally blown, cutting 0E and spacing the leads, and applying a base to said bulb.

14. The method of making a miniature incandescent electric lamp, comprising feeding a sealed glass tube to heating means to soften and puddle a portion adjacent the sealed end, applying a shouldered mold around said softened portion, blowing a bulb in said mold so that the shoulder portion leaves a base-edge-receiving groove, cutting oif the sealed end of said tube to leave an open neck portion, in addition to the tubular portion at the other end thereof, heating said last mentioned tubular portion to provide a contraction therein, feeding lead wires through a mount bead, consolidating said bead with said lead wires, crimping a iilament on the ends of said wires, inserting the mount so formed in said bulb, and positioning it at the proper sealing height, heating the neck portion of said bulb to melt it around the leads of said mount and sealing the latter in said bulb, employing air pressure to stretch the seal, exhausting said bulb through the tube from which it was originally blown, cutting olf and plsging the leads, and applying a base to said 15. In combination, a bulb having a bead mount the bare leads of which are directly consolidated with a neckfportion independent of the opposite end oi' said bulb, said neck portion being provided with an angular groove molded therein, and a base having Van edge portion fitting said groove and cemented to said bulb.

16. The method of making a lamp, comprising blowing a bulb in a tube intermediate the ends thereof, so that tubular portions of normal size extend in opposite directions from said bulb, while rotating in a bearing supporting one end of said tube, introducing a mount into one of said tubular portions, and exhausting said bulb through said other tubular portion.

17. The method of making a lamp. comprising introducing compressed air into one end of s tube to blow a bulb intermediate the ends thereof, while rotating in a bearing supporting one end of said tube, sealing a mount into the other end of said '.tube, and evacuating said bulb through the first-mentioned end of -said tube'.

18. The method of making a miniature incandescent electric lamp, comprising inserting a sealed end of a glass tube in a holder, rotating said tube in said holder while softening and puddlinga portion adjacent the sealed end, applying a shouldered mold around said softened portion, applying air pressure to said tube to blow a bulb in said mold so that the shouldered portion leaves a baseedge-receiving groove, cutting oi! the sealed end of said tube to leave an open neck portion, in addition to the tubular por..

tion at the other end thereof, heating to reduce the section of said last-mentioned tubular portion, introducing a bead-mount in said open neck portion to the proper sealing height, heating said neck portion to consolidate it around the leads adjacent the sealed end, applying a mold around said softened portion, blowing a bulb in said mold, cutting on the sealed end of said tube to leave an open neck portion, in addition to the tubular portion at the other end thereof, heating said last-mentioned tubular portion to provide a contraction therein, feeding lead wires through aper tures in a block so that end portions extend from said block, incorporating parts with said end portions for making a mount before cutting said lead wires to length, bringing said open neck portion into cooperative position with respect to said block and about said mount, in order to dispose the latter in the proper sealing relation to said bulb, heating the neck portion of said bulb to melt it around said leads, sealing the latter in said bulb, pulling down on said leads to stretch the seal, exhausting said bulb, and cutting off and spacing said leads.

WALTER E. CARPENTER.. 

